Knitting machine actuators

ABSTRACT

An improved knitting machine includes a plurality of interchangeable modules each of which is disposed at a knitting station and contains a vertical column of electromagnetic actuators. Each electromagnetic actuator has a generally E-shaped frame with a coil mounted on a center leg of the frame. The coil is energizable to attract an armature which has an outer end of hardened metal and is utilized to cam a needle selector jack from a knit position to a nonknit position. A pair of low friction pivot connections are formed between the armature and E-shaped frame by positioning the inner end of the armature in a pair of open recesses disposed on the outer legs of the frame. The inner end of the armature is held in the open recesses by a beam spring. The beam spring also biases the armature against movement toward an actuated position under the influence of a magnetic field emanating from the coil. Since the magnetic attraction force applied by the coil to the armature increases at an increasing rate as the armature approaches the coil, a second spring assists the beam spring in opposing movement of the armature after it has started to move toward the coil. Due to the cooperation between the two springs and the armature, the total biasing force applied to the armature increases at a greater rate toward the end of an operating stroke of the armature than at the beginning of the operating stroke to prevent excessive armature acceleration and rebound.

United States Patent 1191 Christiansen et al.

[ 1 July 29, 1975 KNITTING MACHINE ACTUATORS [75] Inventors: PaulChristiansen, Novelty; Walter A. Hofmann, Lyndhurst, both of Ohio;Werner Muller, Farmington, Conn.

[73] Assignee: Hayes-Albion Corporation,

Norristown, Pa.

221 Filed: Jan. 9, 1973 121 Appl. NO.I 322,132

[52] US. Cl 156/50 R [51] Int. Cl D04b 15/78 [58] Field of Search 66/50R, 25, 75

[56] References Cited UNITED STATES PATENTS 3,387,188 6/1968 Euler 66/50R ux 3,518,845 7/1970 Dc Ccrjat.. 66 50 R 3,530,686 9/1970 Martinetz66/50 R 3,550,398 12/1970 Widdowson... 66/50 R 3,605,448 9/1971 Ribler66/75 UX 3,695,060 10/1972 Flad 66/75 3,724,240 4 1973 Flad 66/50 R3,733,855 5/1973 BIISS-HIII ct al.. 66/50 R 3,742,733 7/1973 Pacpke66/50 R FOREIGN PATENTS OR APPLICATIONS 1,500,569 9/1967 France 66/751,204,424 9/1970 United Kingdom 66/25 Primary Examiner-Wm. CarterReynolds [57] ABSTRACT An improved knitting machine includes a pluralityof interchangeable modules each of which is disposed at a knittingstation and contains a vertical column of electromagnetic actuators.Each electromagnetic actuator has a generally E-shaped frame with a coilmounted on a center leg of the frame. The coil is energizable to attractan armature which has an outer end of hardened metal and is utilized tocam a needle selector jack from a knit position to a nonknit position. Apair of low friction pivot connections are formed between the armatureand E-shaped frame by positioning the inner end of the armature in apair of open recesses disposed on the outer legs of the frame. The innerend of the armature is held in the open recesses by a beam spring. Thebeam spring also biases the armature against movement toward an actuatedposition under the influence of a magnetic field emanating from thecoil. Since the magnetic attraction force applied by the coil to thearmature increases at an increasing rate as the armature approaches thecoil, a second spring assists the beam spring in opposing movement ofthe armature after it has started to move toward the coil. Due to thecooperation between the two springs and the armature, the total biasingforce applied to the armature increases at a greater rate toward the endof an operating stroke of the armature than at the beginning of theoperating stroke to prevent excessive armature acceleration and rebound.

40 Claims, 14 Drawing Figures PATENTEDJULZSIBYS 3,896,639

' Sriiii 1 FIG! PATENTEB JUL 2 91975 21 g, FIG? V 0 %06 FIGS 5/ TENIEUJUL29 I975 S HE ET F93 Eff FLMZ Y amen/Am 1 POSITION RTURE TEA VL-Znan/470R COIL VOLTAGE FIGIZ KNITTING MACHINE ACTUATORS BACKGROUND OF THEINVENTION This invention relates generally to a knitting machine andmore specifically to a knitting machine having an electromagneticactuator arrangement for effecting movement of a selector jack.

A circular knitting machine having needles which are moved by selectorjacks is disclosed in U.S. Pat. application Ser. No. l5(),052, filedJune 4. 1971 by Horst Paepke and entitled Knitting Machine, now US. Pat.No. 3,742,733. The selector jacks are moved by electromagnetic actuatorswhich are arranged in vertical columns at each of the knitting stations.In one embodiment. the actuator includes a coil which is energized topivot a cam member or armature into position to move a selector jackbetween knit and nonknit positions. In addition. knitting machineshaving electromagnetic jack actuators are disclosed in British Pat. No.1.224.000, published Mar. 3. l97l and in German Pat. No. 1.585.229having an Auslegetag date of Nov. 12. I970.

SUMMARY OF THE PRESENT INVENTION The present invention providesinterchangeable actuator modules which are utilized in a knittingmachine. Each of these actuator modules contains a single verticalcolumn of electromagnetic actuator assemblies. The actuator assembliesare positioned relative to selector jack butts by engagement of outerlegs of a generally E-sha'ped frame with register surfaces in a module.A coil is disposed on an inner leg of the frame and is energizable tomagnetically attract a pivotal armature member. This armature member hasan outer end portion formed ofa relatively hard wear resistant metalwhich engages the selector jack butts to cam the jacks between knit andnonknit positions.

As the armature is pivoted from an unactuated position to an actuatedposition under the inluence of a magnetic field emanating from the coil,the magnetic attraction force on the armature increases at an increasingrate. If unopposed, the rapidly increasing magnetic attraction forcewould cause excessive armature acceleration and rebound. To prevent thisfrom occurring. a pair of spring arrangements cooperate with thearmature to provide a biasing force which increases at a relatively lowrate during initial movement of the armature and increases at arelatively high rate as the armature approaches the actuated position.The biasing force tends to minimize rebounding of the armature byincreasing in a manner which to some extent approximates the manner inwhich the magnetic force of attraction on the armature increases.

The armature is pivotally connected with the outer legs of the E-shapedframe in such a manner as to tend to minimize frictional forces betweenthe armature and frame to facilitate construction of the electromagneticactuator assembly. The inner end of the armature is received in a pairof recesses. each of which is disposed on one of the legs of the frame.Each recess has a bottom portion and an outwardly facing opening throughwhich the armature member extends. The only force holding the armaturein the pair of recesses is provided by one of the biasing springarrangements. This biasing spring arrangement includes a beam typespring which is connected with the two outer legs of the E-shaped framemember and the armature. To prevent excessive wear, the outer endportion of the armature is formed of a relatively hard metal.

Accordingly it is an object of this invention to provide a new andimproved knitting machine having a plurality of interchangeable actuatormodules in each of which electromagnetic actuators are stacked in avertical column.

Another object of this invention is to provide a new and improvedactuator assembly for use in effecting movement of knitting machineselector jacks and wherein the actuator assembly is relatively compact,has a long service life, and has an armature which is movable betweenunactuated and actuated positions without excessive rebound.

Another object of this invention is to provide a new an improvedactuator assembly for effecting movement of a knitting machine jackbetween a knit and nonknit position and which includes a coil which isenergizable to attract an armature with a magnetic force which increasesat an increasing rate as the armature moves toward the coil, and a pairof spring arrangements which cooperate during movement of the armatureto provide a biasing force which increases at an increasing rate duringa final portion of the movement of the armature.

Another object of this invention is to provide a new and improvedactuator assembly for effecting movement of a knitting machine jackbetween knit and nonknit positions and wherein the actuator assemblyincludes generally E-shaped frame member with a coil disposed on acenter leg section and a pivotal armature connected with the outer legsections.

Another object of this invention is to provide a new and improvedknitting machine actuator assembly having an armature member which ismounted for pivotal movement from an'unactuated position to an actuatedposition and wherein an armature mounting arrangement includes a pair ofrecesses having bottom portions and openings facing toward the outer endof the armature member. and a spring to press the inner end of thearmature member against the bottoms of the recesses to retain thearmature member against outward movement.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects andfeatures of the present invention will become more apparent upon aconsideration of the following description taken in connection with theaccompanying drawings wherein:

FIG. 1 is a fragmentary sectional view illustrating the relationshipbetween a vertical column of electromagnetic actuator assemblies in anactuator module and needle selector jacks at a knitting station;

FIG. 2 is an enlarged plan view, taken generally along the line 22 ofFIG. 1, illustrating the relationship between one of the actuatorassemblies and positioning surfaces formed in the module;

FIG. 3 is a side elevational view of an actuator module with otherportions of the knitting machine re moved for purposes of clarity ofillustration;

FIG. 4 is an elevational view. taken generally along line 4-4 of FIG. 3,illustrating a front face of the module;

FIG. 5 is an elevational view taken generally along line 5-5 of FIG. 3,illustrating a rear face of the module;

FIG. 6 is a pictorial illustration of one of the electromagneticactuator assemblies;

FIG. 7 is an enlarged plan view similar to FIG. 2 and taken generallyalong the line 77 of FIG. 6, illustrating the relationship between aframe. coil and armature of the actuator assembly;

FIG. 8 is a side elevational view, taken generally along the line 88 ofFIG. 7, illustrating the relationship between the armature. coil andframe of the actuator assembly of FIG. 7, the armature being shown indashed lines in an unactuated position and in solid lines in an actuatedposition;

FIG. 9 is an end view. taken generally along line 9-9 of FIG. 6,illustrating the relationship between the armature, a beam-type biasingspring arrangement. and a coil type biasing spring arrangement;

FIG. 10 is an enlarged fragmentary sectional view. of the area l0-10 ofFIG. 8, illustrating a low friction pivot mounting arrangement for thearmature;

FIG. 11 is a pictorial illustration of the frame of the actuatorassembly with the coil and armature removed for purposes of clarity ofillustration;

FIG. 12 is a graph illustrating the relationship between time, theduration of current pulse applied to the coil of the actuator assembly,and the position of the armature;

FIG. 13 is a graph depicting the relationship between the rate of changeofthe magnetic attraction applied to the armature by the coil and thebiasing forces applied to the armature by a beam and coil springarrangements; and

FIG. 14 is a schematic illustration of an electrical circuit forapplying a current pulse to the coil of an actuator assembly.

DESCRIPTION OF ONE EMBODIMENT General Description A circular knittingmachine has a plurality of knitting stations 22 (only one of which isshown in FIG. I with an actuator module 24 disposed at each of theknitting stations. The actuator module 24;includes a plurality ofimproved actuator assemblies 28 which are disposed in a vertical column30 (some of the actuator assemblies have been omitted from FIG. I forpurposes of clarity of illustration). Each of the actuator assemblies 28is selectively energizable to move an associated needle selector jack 32between knit and nonknit positions. The actuator assemblies 28 aresupported in the module 24 by engagement of a generally E-shaped frame36 (see FIGS. I and 2) with horizontally extend ing support slots 38formed in vertically extending support walls 42 and 44 (FIG. 2).

Each of the actuator assemblies 28 includes a coil 48 which isselectively energizable to pivot an armature 52 from an unactuatedposition (shown in dashed lines FIG. 8) to an actuated position(shown insolid lines in FIG. 8) against the influence of a beam or bar typespring 54 (FIG. 9) and a coil spring 58. Upon initial movement of thearmature 52 from the unactuated position toward the actuated position.the beam spring 54 opposes movement of the armature 52 with a biasingforce which increases in a linear manner depicted by curve 64 in FIG.13. As the armature member 52 continues to move toward the actuatedposition. the coil spring 58 becomes effective to apply a biasing whichalso increases in a linear manner. as depicted by a curve 66 in FIG. 13.

As the armature 52 moves toward the actuated position and the coil 48,at an increasing rate (see curve 68 in FIG. 13). If unopposed. thisrapidly increasing magnetic force would case excessive rebounding of thearmature 52 from the actuated position. The use of a single biasingspring, such as the beam spring 54, is effective to reduce the amount ofarmature rebound. Howe\ er. since the biasing force applied by the beamspring 54 increases in a linear manner, it is ineffective to fullycompensate for the increasing rate of change of the magnetic attractionforce. To more fully compensate for the increasing rate of change of themagnetic attraction force. the beam and coil springs 54 and 58 provide atotal or combined biasing force (curve 70 of FIG. I3) which increases ata greater rate toward the end of an armature stroke than the biasingforce applied by only the beam spring 54. This enables the beam and coilsprings 54 and 58 to at least approximate the rate at which the magneticattraction force (see curve 68 in FIG. 13) increases as the armatue 52approaches the actuated position.

To enable the armature 52 to pivot freely between the unactuated andactuated positions of FIG. 8, the ar mature is provided with lowfriction pivot mountings which are similar to knife type bearings. Thearmature 52 is pivotally mounted on the frame 36 at a pair of bearingblocks 76 and 78 (FIGS-6, 7 and 9) disposed on opposite side of the coil48. The bearing blocks 76 and 78 have outwardly opening recesses intowhich the armature 52 projects. Since the recesses are identical. onlythe recess 82 in the bearing block 78 is shown in FIGS. 8 and I0.

Knitting Needle Actuation The knitting machine 20 includes a circularneedle carry cylinder (FIG. I) having a plurality of verticallyextending slots 92 in which knitting needles 94 are carried. A pluralityof jack arrangements 96 are mounted on the carrier cylinder 90 and areoperated by the electromagnetic actuator assemblies 28 to move theassociated knitting needles 94 from the illustrated knit position toanonknit position the needle cylinder 90 is rotated about a verticalcentral axis relative to a base I00 of the knitting machine 20. Itshould be understood that the term knit position may also refer to thetuck position and that the term nonknit position may refer to the weltposition.

The jack arrangement 96 includes 'a needle moving jack 104 having anouter end which is pivotally connected with an associated end of one ofthe knitting needles 94. Each needle moving jack I04 has a butt I06which is movable in a cam track 107 to effect raising and loweringmovement of the associated knitting needle 94. In addition. each of thejack arrangements 96 includes a vertically extending selector jack 32which is operable to effect pivoting movement of the needle raising jackI04 to remove the butt I06 thereof from the cam track I07 so that theneedle will not be raised through a knitting stroke as it moves througha knitting station 22.

Each of the selector jacks 32 has a butt I14 which may be engaged by thearmature 52 of an associated one of the electromagnetic actuatorassemblies 28 during movement of the jack butt through the knittingstation 22. Engagement with the armature 52 pivots the selector jack 32in a counterclockwise direction about its lower end portion 118 andeffects movement of the butt I06 of the needle jack I04 out of the camtrack 107. In the specific embodiment of the invention illustrated inthe drawings. the selector jacks 32 are deposited in echelon groups ofthirteen jacks with the butts 114 of the jacks offset vertically. Thereare I3 electromagnetic actuator assemblies 28 in each actuator module24. Each of the actuator assemblies 28 is associated with the jack butts114 at a particular level. Thus. dur ing rotation of the needle cylinder90, the uppermost electromagnetic actuator assembly 28 is operable toengage the uppermost butt I14 in an echelon group of selector jackbutts. Similarly. the next lower actuator assembly 28 engages the nextlowerjack butt in an echelon group.

The operation of the selector jack 32 and needle jacks 104 inassociation with each one of the knitting needles 94 is more thoroughlydescribed in the aforementioned U.S. Pat. application Ser. No. 150.052.filed June 4. I97] by Horst Paepke. The controls for activating theelectromagnetic actuator assemblies 28 to move the associated one of thejack butts 114 between the knit and nonknit positions are the same asdisclosed in US. Pat. application Ser. No. 193.047. filed Oct. 27. 1971by Paul Christiansen and entitled Knitting Machine Control." An encoderarrangement similar to the one disclosed in application Ser. No.192,984. filed Oct. 27. I971 by Ralph H. Schuman and entitled KnittingMachine Encoder" is used in association with these controls. Althoughthe jack arrangement and controls disclosed in these applications arepreferred for use with the electromagnetic actuator assemblies 28, itshould be understood that other jack arrangements and controls beutilized if desired.

Although only a single knitting station 22 is shown in FIG. I. it shouldbe understood that the knitting machine includes a plurality of knittingstations disposed in an annular array about the rotatable needlecylinder 90. At each of these knitting stations is disposed one of thestationary actuator modules 24. Since the actuator modules 24 are ofidentical construction and cooperate with the jack arrangements 96 inthe same way. the actuator modules are interchangeable. Only one of theactuator modules 24 has been shown in FIG. I.

In one specific embodiment of the invention. the circular knittingmachine 20 had 1,872 needles arranged in I44 echelons of 13 needleseach. This illustrative knitting machine had 36 knitting stations 22with an actuator module 24 containing I3 actuator assemblies 28 at eachof the knitting stations. Since each actuator assembly 28 is operable toengage the butt 114 of only one selector jack 32 in each echelon of 13selector jacks. the actuator assembly 28 must be capable of operatingwith sufficient speed to move the armature 52 between the unactuated andactuated positions in less time than it takes thirteen needles 94 tomove past a knitting station. The available actuation time is determinedby relating the speed of rotation of the cylinder 90-to the distancebetween I3 needles minus the width of the armature. It should beunderstood that although the electromagnetic actuator assemblies 28 aredescribed herein in connection with a knitting machine 20 having 13needles in each echelon. the actuator assemblies could be utilized inassociation with a knitting machine having a greater or lesser number ofneedles in each echelon.

Actuator Module Each of the actuator modules 24 (FIG. 3) includes abottom section I20 and an upstanding support section 122 in which theactuator assemblies 28 are disposed in a vertically extending array(FIG. I). The upstanding support section 122 positions each of theelectromagnetic actuator assemblies 28 so that the armatures 52 aredisposed slightly below the associated jack butt 1 14 in each echelongroup ofjack butts when the armature is in the unactuatedposition (shownin dash lines in FIG. 8). This enables the selector jack 32 associatedwith an unactuated electromagnetic actuator assembly 28 to move throughthe knitting station without being cammed from the knit position of FIG.I to the nonknit position. However, when the,coil 48 of an actuatorassembly 28 is energized. the armature 52 pivots upwardly into the pathof movement of the butt 114 of the associated selector jack 32.Therefore, the butt 114 of the selector jack 32 associated with theactuated electromagnetic actuator assembly 28 is cammed to the nonknitposition as it is moved through the knitting station 22.

To hold the actuator assemblies 28 in a vertical columnor array. theupstanding support section 122 of the actuator module 24 includes a pairof vertically extending side walls 126 and 128 (see FIGS. 2 and 4). Thesupport walls 126 and 128 are each provided with horizontally extendingslots 38 (FIGS. l and 2) which receive the frames 36 of theelectromagnetic actuator assemblies 28 and support the actuatorassemblies with the central or main axes of the coils 48 extendinghorixontally in a common vertical plane. The slots 38 also function tolocate the actuator assemblies 28 in the proper vertical relationshipwith the selector jacks 32.

The actuator assemblies 28 must be positioned so that the outer endportions of the armatures 52 engage the butts I14 of the selector jacksafter the armatures are moved from their unactuated positions to theiractuated positions. To provide for this positioning of the actuatorassemblies 28. the forward ends of the frames 36 of the actuatorassemblies are engaged by a pair of vertically extending frontpositioning or register blocks I34 and 136 (FIG. 2) which are connectedto the side walls 126 and 128 and have a transversely inwardlyprojecting register surface I40 and 142 which engage the forward orouter end portions of the frames 36. The frames 36 are pressed againstthe vertical register surfaces 140 and 142 by a vertically extendingrear positioning block 146 having a pair of side sections 148 and 150which engage the inner ends of the frames 36 to hold the frames inengagement with the register surfaces 140 and 142. A slotted shield orcover member 154 is provided on the front or forward side of theactuator module 24 to prevent foreign material from interferring withthe operation of the actuator assemblies 28.

Once the actuator assemblies 28 have been positioned within the module24. it is necessary to position the module at one of the knittingstations 22 in the desired orientation relative to the needle cylinder90 and selector jacks 32. To this end. a register plate 158 (see FIGS.1, 3. 4 and 5) is fixedly mounted at each of the knitting stations. Alocating slot 160 (FIGS. 4 and 5) is formed in the register plate 158and extends radially of the carrier cylinder 90. The bottom portion 120of the module frame is provided with a locating tongue 162 which engagesthe slot 160 to position the module 24 along one axis.

Each of the modules 24 is provided with a locating or positioning screwI66 (see FIGS. 3 and 4) which engages a surface 168 (FIG. I) to positionthe module along an axis extending radially to the carrier cylinder 90.Once the locating tongue 162 has been positioned in a slot 160 and thepositioning screw 166 has engaged the register surface 168. the module24 is located in the proper position relative to the actuator jackarrange ment 96. When the module 24 has been so positioned, a bolt 172(see FIG. I) is tightened to securely connect the module 24 with thebase 100 of the knitting machine.

Although the construction ofonly one actuator mod ule 24 has been shownin the drawings. it should be understood that the knitting machine 20includes a plurality of actuator modules 24 of identical constructionwhich are disposed in a circular array about the carrier cylinder 90with one of the actuator modules 24 being located at each of theknitting stations. The actuator assemblies 28 in the actuator modules 24are connected with electrical leads 176 which are enclosed in a cable178 having a plug 180 (FIG. 1) connected with control circuitry for theknitting machine. After a module 24 has been removed from a knittingstation 22, the identical construction of the modules enables a sparemodule to be positioned at the knitting station.

Once the actuator module 24 has been removed from the knitting station22, a cover 184 is removable to provide access to the interior of themodule. Each of the actuator assemblies 28 is connected with theelectrical leads 176 by a plug 188 (FIG. 2) and connector jacks 190 and192. The jacks I90 and 192 extend through the positioning member 146into engagement with an electrical connector 194 which is connecteddirectly to the coil 48.

Actuator Assembly Frame Each of the actuator assemblies 28 includes agenerally E-shaped frame 36 (see FIG. 11) which is stamped from a singlepiece of slicon core iron which is readily magnetized by energization ofa coil 48 (FIG. 7) and has a low residual magnetism when the coil isdeenergized. The frame 36 includes a relatively long center leg 200(FIG. 11) which extends through the center of the coil 48. A pair ofside legs 204 and 206 are disposed on opposite sides of the center leg200 and extend parallel to the center leg. The side legs 204 and 206 areslightly shorter in length than the center leg 200 so that the bearingblocks 76 and 78 which pivotally support the armature 52 can be mountedon the ends of the side legs (see FIG. 7) with the center leg 200extending outwardly of the bearing blocks. This enables the center leg200 to overlie the armature 52 and provide a strong magneticinterconnection between the armature and frame 36 upon energization ofthe coil 48.

The side legs 204 and 206 of the frame 36 are provided with positioningprojections 220., 222, 224 and 226 (FIG. 7) engage the bottom of theslots 38 in the side walls 126 and 128 of the actuator module 24 (FIG.2) to position the frame 26 transversely relative to the side walls. Theframe 36 is also provided with a rearwardly projecting positioningsection 230 which is engaged by the positioning member 146 to press theouter end portions 210 and 212 (FIG. 11) of the frame 36 against theregister surfaces 140 and 142 (FIG. 2). Thus. the integrally formedframe member 36 is provided with positioning sections which are utilizedto locate the actuator assembly 28 along a horizontal central axis whichextends radially from the needle cylindcr 90 and along a horizontal axisextending perpendicular to this radial axis. Armature Mounting Tominimize frictional resistance to pivotal movement of the armature 52between the unactuated position (shown in dashed lines FIG. 8) and theactuated position (shown in solid lines in FIG. 8), the armature isconnected with the frame 36 at low friction bearing connections 232 and233 (FIGS. 7 and 9) which are similar to knife edge bearings and have along service life. The generally knife type bearing connections areformed between outwardly projecting side arm sections 234 and 236 of thearmature 52 and the bearing support blocks 76 and 78. The connection 232between the arm section 236 and the bearing support block 78 is clearlyset forth in FIG. 10 wherein the armature 52 is shown in dashed lines inan unactuated position and in solid lines in the actuated position. Whenthe armature 52 is in the unactuated position. a first corner of apex240 formed by the intersection of a bottom or major surface 242 and arear or minor surface 244 engages a flat bottom surface 248 of therecess 82. Upon energization of a coil 48 and movement of the armature52 to the actuated position (shown in solid lines in FIG. 10) the endsurface 244 of the armature 52 is disposed in flat abutting engagementwith the bottom surface 248 of the recess 82. This flat abuttingengagement between the end surface 244 of the armature 52 and bottomsurface 248 of the recess 82 provides a relatively large surface area totransmit shock loading applied to the armature 52 by engagement with ajack butt 114. A true knife edge bearing could be damaged by such aloading. Of course. upon de-energization of the coil 48 the armaturepivots about the corner 240 from the actuated position to the unactuatedposition.

Although the connection between the armature 52 and bearing block 78 maynot be considered as a true knife edge bearing due to the fact that theend surface 244 of the armature moves into flat abutting engagement withthe bottom surface 248 of the recess 82 when the armature 52 is in theactuated position. the connection between the armature 52 and bearingblock 78 provides most if not all of the advantages of a true knife edgebearing. Thus. there is a relatively low friction force opposingmovement of the armature S2 relative to the bearing block 78. Inaddition. the simple interconnection between the armature 52 and bearingblock 78 is relatively trouble free so that the actuator assembly 28 hasa relatively long service life with a minimum amount of maintenance.Although only the interconnection between the armature 52 and thebearing block 78 is shown in FIG. 10. it should be understood that thearm 234 of the armature member 52 has a second corner or apex andcooperates with the bearing block 76 in the same manner as in which thearm 236 cooperates with the bearing block 78.

The beam type spring 54 urges the inner end portions of the arms 234 and236 into abutting engagement with the recesses 82 in the bearing blocks76 and 78. Thus. a connector arm or hook 252 extends downwardly from thecenter portions of the armature 52 (see FIGS. 9 and 10) into engagementwith the beam spring 54. The beam spring 54 applies a force to theconnector arm or hook 252 urging the armature 52 toward the right (asviewed in FIG. 10). This force presses the inner or rearward end of thearmature 52 against the bottom 248 of the recess 82. It should be notedthat the recess 82 has a generally rectangular opening having a verticalextent which is greater than the thickness of the armature 52 so thatthe armature can be moved freely into and out of the recess. However.the beam spring maintains the inner end of the armature 52 in abuttingengagement with the bottom 248 of the recess 82. The verticallyextending bottom surface 248 of the recess has a vertical height whichis only slightly greater than the thickness of the armature 52 so thatthe inner end of the armature can lay flat against the bottom surface248. The recess 82 is provided with a downwardly sloping lower sidesurface 260 which is engaged by the lower surface 242 of the armature 52when it is in the unactuated position.

The beam spring 54 includes a pair of generally straight longitudinallyextending spring rods or wires 266 and 268 (FIG. 9) which extend througha pair of passages formed by holddown tabs 272 and 274. The spring rods266 and 268 are resiliently deflected upwardly by a relatively smallamount when the armature 52 is in the unactuated position (shown indashed lines in FIG. 8). Upon pivotal movement of the armature 52 to theactuated position (shown in solid lines in FIG. 8) the connector hook orarm 252 increases the deflection of the spring rods 266 and 268 throughthe movement of the connector arm 252 relative to a pair of supportplates 278 and 280 in which the holddown tabs 272 and 274 are formed andto which the ends of the spring rods 266 and 268 are connected. Thesupport plates 278 and 280 are connected to the bottom of the outerframe arms 204 and 206 (FIG. 6). One of the support plates. that is thesupport plate 280, has an outwardly projecting stop arm 284 which limitsdownward movement of the armature 52 during handling of the actuatorassembly 28 outside of the module 24.

To reduce the passage of magnetic flux from the outer legs 204 and 206to the center leg 200 (FIG. 11) of the frame 36 without passing throughthe armature 52, the support plates 278 and 280 are formed of anonmagnetic material. such as stainless steel. The passage offlux fromthe outer frame legs 204 and 206 to the armature 52 is promoted by thebeam spring 54. The beam spring rods 266 and 268 are formed of amagnetizable material and extend from a location adjacent to the ends ofthe outer frame legs 204 and 206 to the connector arm 252 which isintegrally formed with the armature 52 (FIG. 9). This provides a minimumair gap between the armature 52 and outer frame legs 204 and 206 topromote the passage of flux to the armature. Armature Movement Uponenergization of the coil 48, the armature 52 moves from an unactuatedposition (indicated by the portion 304 of the curve 290 in FIG. 12)toward a fully actuated position indicated by portion 292 of the curve290. Before the armature reaches the fully actuated position. it reachesa position in which the outer end portion of the armature will interferewith the butt 114 of an associated selector jack 32. this position beingindicated by the line 296 in FIG. 12. As the armature 52 moves upwardlytoward the actuated position. it engages an upper stop surface 287formed on the slotted shield or cover member 154 (FIG. 8). and tends torebound in the manner indicated by the irregular line 298 (FIG. I2).However. this rebound is not great enough to cause the armature 52 tomove to a position in which it will not engage the jack butt H4. To tendto minimize armature rebound. the shield I54 is formed of an energyabsorbing material. such as synthetic rubber. Of course. other knownenergy absorbing material could be used if desired.

If the next needle 94 is to be cammed to the nonknit position, theactuator assembly 28 remains energized. However, if the next needle isto knit. the coil 48 is deenergized and the armature 52 moves downwardlyfrom the actuated position toward the unactuated position in a mannerrepresented by the portion 300 of the curve 290 (FIG. 12). As thearmature moves downwardly. it moves to a position (represented by line304 in FIG. I2) in which it is substantially below the associated jackbutt 114 and will not interfere with the next succeeding jack butt. Asthe armature 52 reaches the unactuated position it engages a lower stopsurface 288 on the shield 154 (FIG. 8) and tends to rebound, asindicated by the irregular line 306. Of course. the lower stop surface288 is also made of an energy absorbing material so that rebounding ofthe armature is minimized.

To effect rapid movement of the armature 52 from the unactuated positionto the actuated position. a relatively high forcing voltage (V,) issupplied to the coil 48 in the manner illustrated by the portion 307 ofthe curve 308 in FIG. 12. This relatively high forcing voltage is thenreduced to a holding voltage (V,,) indicated by the portion 309 of thecurve 308. The relatively high initial forcing voltage causes thecurrent connected to the coil 48 to quickly increase in the manner shownby the portion 310 of the curve 31] in FIG. 12. Of course. once thevoltage applied to the coil 48 decreases to the holding voltage(indicated by the portion 309 of the curve 308) the current flow throughthe coil 48 reduces to a holding value indicated by the portion 312 ofthe curve 311.

Upon de-energization of the coil 48. the collapsing of the magneticfield causes an instantaneous negative voltage. indicated by the portion313 of the curve 308. As the coil voltage returns to zero. the currentflow through the coil drops to Zero as shown in the portion 314 of thecurve 311. This results in the armature S2 returning to the unactuatedposition under the influence of the beam spring 54 and coil spring 58.It should be noted that the upper surface 287 prevents the armature 52from striking the center leg 200 of the frame 36 to prevent wear andmagnetic sealing between the frame and armature.

As the armature 52 moves from the unactuated position to the actuatedposition. the force of magnetic attraction applied to the armature bymagnetic field emanating from the coil 48 increases in a nonlinearmanner. Thus. during initial movement of the armature 52 from theunactuated position. the force of magnetic attraction applied to thearmature increases at a relative low rate. However. as the armatureapproaches the center leg or pole piece 200 of the coil 48, the force ofmagnetic attraction increases at an increasing rate in the mannerdepicted schematically by the curve 68 in FIG. 13.

The biasing force applied by the beam spring 54 resisting movement ofthe armature from the unactuated position to the actuated positionincreases at a constant rate with movement of the armature from theunactuated position toward the actuated position. This is because theamount of deflection of the beam spring 54 increases at a constant ratewith movement of the armature 52 toward the actuated position. Duringinitial movement of the armature 52 from the unactuated position towardthe actuated position. the biasing force applied to the armature by thebeam spring 54 is somewhat less than magnetic attraction force andincreases in a manner which is generally similar to the manner in whichthe magnetic attraction force applied to the armature increases. Thus.during initial movement of the armature 52, the beam spring force.represented by the line 64 in FIG. 13, increases in a manner generallysimilar to the manner in which the magnetic attraction force increases,shown by the curve 68 in FIG. 13.

Approximately midway through the travel of the armature 52. the magneticattraction force begins to increase at a substantially greater rate thanthe rate which the beam spring force increases. Due to the rela tivelyrapid rate of increase in the magnetic attraction force. if only thebeam spring arrangement 54 applied a biasing force to the armature 52,the armature would accelerate greatly as it moved toward the actuatedposition. This acceleration would increase the rebound of the armaturefrom the actuated position.

To prevent excessive rebound of the armature from the actuated position,the coil spring 58 becomes effective to apply a biasing force to thcarmature part way through an operating stroke. The force applied to thearmature by the coil spring 58 is represented by the line 66 in FIG. 13.Due to the influence of the coil spring 58 which circumscribes springguide 315, the total biasing force applied to the armature 52 increasesat an increasing rate as the armature approaches the actuated positionrepresented by the lines 316 in FIG. 13. Due to the biasing effectapplied by the coil spring 58, the acceleration of the armature 52 isretarded so that it does not rebound excessively from the actuatedposition. It should be noted that the coil spring 58 is not effectiveuntil the armature has travelled part way between the actuated andunactuatcd positions, represented by the lines 318 in FIG. 13. At thistime the lower end portion of the coil spring 58 engages the bottom ofarecess 320 (FIG. 9) formed in the armature 52 and is effective to regardmovement of the armature in conjunction with the beam type biasingspring 54. The energy stored in the coil spring 58 enables it to promoterapid movement of the armature 52 from the actuated position to theunactuated position.

A circuit 324 (FIG. 14) provides a pulse of current (represented by thecurve 308 in FIG. 12) to energize coil 48. The circuit 324 includes alead 326 which is connected with a positive voltage source and the coil48. The coil 48 is connected to ground through a transistor 328. Thetransistor 328 is rendered conducting by a signal 329 (FIG. 12)transmitted to the base of the transistor 328 by control circuitryconnected with a lead 330 when the coil 48 is to be energized to effectmovement of a selector jack 32 from the knitting position to thenonknitting position.

To provide a relatively large forcing voltage. represented by theportion 307 of the curve 308 of FIG. 12. the circuit 324 (FIG. 14) isprovided with a capacitor 331 which is charged with a relatively highforcing voltage while the transistor 328 is turned off. Thus. thecapacitor 331 is connected with a relatively high voltage source (Vthrough resistor 332. The charge rate for the capacitor 331 is such thatthe capacitor will charge to a sufficiently high voltage when theactuator is being operated at the maximum rate required for a particularmachine. In one specific embodiment of the invention (ill the forcingvoltage (V was approximately four to five times the holding voltage(V,,).

When the transistor 320 is turned on by the signal 329 (FIG. 12)directed to the base of the transistor. the relative high forcingvoltage (V on the capacitor 331 appears across the actuator coil 48 asindicated by the portion 307 of the curve 308 in FIG. 12. This causesthe current to build up rapidly (see portion 310 of the curve 311 inFIG. 12). When the charge on the capacitor 331 has been reduced. theholding voltage (V,,) is supplied through a diode 333 to the coil -88(see portion 312 of the curve 311 in FIG. 12). Although some of theholding current is supplied by the forcing voltage source (V through theresistor 332. this current is not sufficient to hold the armature 52 inthe actuated position. A diode 334 limits the voltage at the collectorof the transistor 328 to the forcing voltage (V when the transistor 328is turned off and the actuator field 48 collapses.

When the armature 52 is in the actuated position. an outer end portion340 (see FIG. 7) is disposed in the path of movement of a jack butt 114which is in a particular position in the echelon formation of jackbutts. The outer end portion of the armature S2 is formed of arelatively hard tool steel to enable it to withstand wear induced byengagement with the jack butts 114. The remainder of the armature 52 isformed of a relativcly soft material. such as low carbon I .010 steel)to provide a relatively low residual magnetism upon deenergization ofthe coil 48.

Since the arms 234 and 236 of the armature 52 are disposed in pressureengagement with the outwardly opening recesses 82 in the bearing blocks76 and 78. it is advantageous to have the force applied to the armature52 by engagement with one of the jack butts 114 which tends to cause thearmature to pivot about a center disposed between the two bearing blocks76 and 78. If the armature 52 tended to pivot about a center disposedoutwardly of one of the bearing blocks. the armature would tend to moveaway from the other bearing block. For example. if the force is appliedto the armature 52 by engagement with one of the jack butts I14 resultedin a moment of torque tending to pivot the armature about a centerdisposed to the outer side of a bearing block 76. the arm 236 of thearmature would tend to move away from the bearing block 78.

To tend to minimize movement of the armature arm 236 away from thebearing block 78 when the armature engages a jack butt 114. the armature52 has a main or body portion 344 extending outwardly from the arms 234and 236 for a short distance. A cam surface 348 on the outer end of thebody 344 is disposed at an angle (indicated at 350 in FIG. 7) of between13 and 25. The combination of the relatively short body portion and camangle results in the armature 52 tending to pivot about a center whichis located between the bearing blocks 76 and 78 when the cam surface 348engages a jack butt 114. Therefore. the arm 236 of the armature does nottend to move away from the bearing block 78.

Due to friction between the armature S2 and cam surface on an associatedjack butt 114 and/or other causes. the armature 52 may tend to rotateabout a center outside of the bearing block 76. If this occurs. thearmature 52 is engaged by a hardened steel stop block or panel 351 (FIG.4) to prevent the armature arm 236 from moving out of the recess in thebearing block 78.

In one specific embodiment of the invention the clearance between thearmature 52 and stop panel 351 was between 0.001 and 0.002 of an inch.It should be understood that the foregoing dimensions are merelyillustrative and could vary.

The actuator assembly 28 at the top of the column 30 (FIG. 1) ofactuator assemblies must move a selector jack butt 114 through a largerdistance than an actuator assembly 28 at the bottom of the column 30.This is because the selector jacks 32 pivot about their lower endportions 118 when they move from the knit position to the nonknitposition. Accordingly. the cam angle 350 on an armature 52 at the top ofthe column 30 is greater than the cam angle on an armature at the bottomof the column. The jack butts 114 associated with actuator assemblies 28adjacent to the top of the column 30 project further from the body ofthe selector jack 32 than do the jack butts 114 associated with actuatorassemblies adjacent to the bottom of the column.

In one specific embodiment of the invention, the cam angle 350 on thearmature 52 of the actuator assembly 28 at the top of the column 30 wasThe cam angle on the armatures 52 of the actuator assemblies 28 betweentop and bottom of the column decreased in a proportional manner to a camangle of 13 at the bottom of the column. The extent to which theselector jack butts 114 projected also decreased in a uniform mannerfrom a relatively large projection for the uppermost jack butt of anechelon group of jack butts to a relatively small projection for thelowermost jack butt in the echelon group ofjack butts. Ofcourse, otherspecific cam angles could be utilized as required. Conclusion In view ofthe foregoing description. it will be seen that the knitting machine 20includes a plurality of interchangeable actuator modules 24 each ofwhich is disposed at one of a plurality of knitting stations 22.

The actuator modules 24 are of identical construction'--.

and contain a single vertical column or array ofelectromagneticactuators 28. Each of these electromagnetic actuators 28 has a generallyE-shaped frame 36 with outer legs 204 and 206 disposed in engagementwith register surfaces 140 and 142 to position an actuator assembly 28in the module 24. A coil 48 is mounted on a horizontal center leg of theE-shaped frame member 36 and is energizable to attract an armature 52which has an outer end portion 340 of a hardened metal to cam a needleselector jack 32 from a knit position to a nonknit position.

A pair of arms 234 and 236 of the armature member 52 have inner endportions disposed in a pair of open recesses 82 formed in bearing blocks76 and 78 mounted on outer ends of the legs 104 and 206 of the framemember 36. Although the sides of the recesses 82 are spaced apart by asufficient distance to enable the armature 2 to be freely withdrawn fromthe recesses, the armature is held in the recesses by a beam spring 54.Since the magnetic force applied by the coil 48 to the armature 52increases at an increasing rate as the armature approaches the coil, asecond spring 58 assists the beam spring 54 in opposing movement of thearmature after the armature has started to move toward the coil 48. Dueto the cooperation between the two springs 54 and 58. the total biasingforce applied to the armature 52 by the springs increases at a greaterrate toward the end of the operating stroke of the armature than at thebeginning of the stroke.

Having described one specific preferred embodiment of the invention, thefollowing is claimed:

1. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station, a plurality ofjack means each of which is associated with one of said needles and isoperable between knit and nonknit conditions, and a plurality ofactuator means disposed at the knitting station for effecting operationof said jack means between the knit and nonknit conditions, each of saidactuator means including coil means energizable to provide a magneticfield, a frame member having a plurality of parallel interconnected legsections including a first leg section extending through said coilmeans, a second leg section disposed on one side of said first legsection, and a third leg section disposed on a side of said first legsection opposite said one side, an armature member movable under theinfluence of a magnetic field emanating from said coil means, andmounting means connected with said second and third leg sections forsupporting said armature member for pivotal movement between a firstposition in which said armature member is ineffective to operate one ofsaid jack means between the knit and nonknit conditions and a secondposition in which said armature member is ef fective to operate one ofsaid jack means between the knit and nonknit conditions, the magneticfield emanating from said coil means of each of said actuator meansbeing effective upon energizati'on thereof to attract said armaturemember with a magnetic force which increases at an increasing rate assaid armature member moves between the first and second positions. eachof said actuator means further including first spring means forproviding a first biasing force opposing movement of said armaturemember between the first and second positions under the influence of themagnetic field emanating from said coil means. and second spring meansfor providing a second biasing force which is effective to opposemovement of said armature member after said armature member has movedpart way between said first and second positions against the influenceof said first biasing force. said first and second spring meanscooperating during movement of said armature member to provide a totalbiasing force which increases at a first rate during an initial portionof the movement of said armature member between the first and secondpositions and which increases at a second rate which is greater than thefirst rate during a final portion of the movement of said armaturemember between the first and second positions.

2. A knitting machine as set forth in cliam 1 further including supportmeans for supporting said actuator means in a linear array at theknitting station, said support means including a first longitudinallyextending support element connected with the second leg section of saidframe members and a second longitudinally extending support elementconnected with the third leg section of said frame members.

3. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station. a plurality ofjack means each of which is associated with one of said needles and isoperable between knit and nonknit conditions. and a plurality ofactuator means disposed at the knitting station for effecting operationof said jack means between the knit and nonknit conditions, each of saidactuator means including coil means energizable to provide a magneticfield, a frame member having a plurality of parallel interconnected legsections including a first leg section extending through said coilmeans. a second leg section disposed on one side of said first legsection, and a third leg section disposed on a side of said first legsection opposite said one side. an armature member movable under theinfluence of a magnetic field emanating from said coil means, mountingmeans connected with said second and third leg sections for supportingsaid armature member for pivotal movement between a first position inwhich said armature member is ineffective to operate one of said jackmeans between the knit and nonknit conditions and a second position inwhich said armature member is effective to operate one of said jackmeans between the knit and nonknit conditions, and spring means forproviding a biasing force opposing movement of said armature memberbetween the first and second positions, said spring means including abeam spring member extending transversely to said leg sections andhaving a central porition connected to said armature member, one endportion connected with said second leg section, and another end portionconnected with said third leg section.

4. A knitting machine as set forth in claim 3 wherein said mountingmeans for each of said actuator means includes a first recess meansconnected with said second leg section for engaging an inner end portionof said armature member at one location and a second recess meansconnected with said third leg section for engaging the inner end portionof said armature member at another location spaced from the onelocation, each of said recess means including a bottom portion disposedinwardly of an outwardly facing opening and through which opening theinner end portion of said armature member extends.

5. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station, a plurality ofjack means each of which is associated with one of said needles and isoperable between knit and nonknit conditions, and a plurality ofactuator means disposed at the knitting station for effecting operationof said jack means between the knit and nonknit conditions, each of saidactuator means including coil means energizable to provide a magneticfield, a frame member having a plurality of parallel interconnected legsections including a first leg section extending through said coilmeans. a second leg section disposed on one side of said first legsection, and a third leg section disposed on a side of said first legsection opposite said side, an armature member movable under theinfluence of a magnetic field emanating from said coil means. andmounting means connected with said second and third leg sections forsupporting said armature member for pivotal movement between a firstposition in which said armature member is ineffective to operate one ofsaid jack means between the knit and nonknit conditions and a secondposition in which said armature member is effective to operate one ofsaid jack means between the knit and nonknit conditions, said mountingmeans for each of said actuator means including a first recess meansconnected with said second leg section for engaging an inner end portionof said armature member at one location and a second recess meansconnected with said third leg section for engaging the inner end portionof said armature member at another location spaced from the onelocation. each of said recess means including a bottom portion disposedinwardly of an outwardly facing opening and through which opening theinner end portion of said armature member extends, each of said actuatormeans further including spring means for opposing movement of saidarmature member between the first and second positions and for pressingthe inner end portion of said armature member against the bottomportions of said first and second recess means.

6. A knitting machine as set forth in claim 5 wherein said spring meansincludes a longitudinally extending spring member connected with saidsecond and third leg sections at its outer end portions, said springmember having a portion disposed betweeen the outer end portionsconnected with said armature member.

7. A knitting machine as set forth in claim 5 wherein apexes formed bythe intersection of side surfaces of said armature member are disposedin abutting engagement with the bottom portions of said first and secondrecess means when said armature member is in one of said first andsecond positions.

8. A knitting machine as set forth in claim 7 wherein one of the sidesurfaces of said armature member is disposed in abutting engagement withthe bottom portion of at least one of said recess means when saidarmature member is in another one of said first and second positions.

9. A knitting machine as set forth in claim 5 wherein said armaturemember of each of said actuator means includes an inner end portiondisposed in engagement with said mounting means and formed of a firstmetal and an outer end portion disposed adjacent to said jack means andformed of a second metal which is harder than said first metal. saidouter end portion of said armature member including cam surface meansformed of said second metal for engaging said jack means.

10. An actuator assembly for effecting movement of a knitting machinejack between knit and nonknit positions, said actuator assemblycomprising armature means movable between a first position in which saidarmature means is ineffective to move the jack and a second position inwhich said armature means is effective to move the jack between the knitand nonknit positions, coil means for moving said armature means betweenthe first and second positions u'pon energization of said coil means,said coil means being energizable to attract said armature means with amagnetic force which increases at an increasing rate as said armaturemeans moves between the first and second positions. first spring meansfor providing a first biasing force opposing movement of said armaturemeans between the first and second positions under the influence of themagnetic force. and second spring means for providing a second biasingforce opposing movement of said armature means between the first andsecond positions after movement of said armature means against the firstbiasing force, said first and second spring means cooperating duringmovement of said armature means to provide a total biasing force whichincreases at a first rate during an initial portion of the movement ofsaid armature means between the first and second positions and whichincreases at a second rate which is greater than the first rate during afinal portion of the move ment of said armature means between the firstand second positions.

H. An actuator assembly as set forth in claim it) further including aframe member having a plurality of interconnected leg sections includinga first leg section extending through said coil. means. a second legsection disposed on one side of said first leg section. and a third legsection disposed on a side of said first leg section opposite said oneside. and mounting means connected with said second and third legsections for supporting said armature means for pivotal movement betweenthe first and second positions.

12. An actuator assembly as set forth in claim I] wherein said firstspring means includes a longitudi nally extending spring memberconnected to said second and third leg sections and said armature meansin termediate the connections to said second and third leg means.

13. An actuator assembly as set forth in claim 10 wherein said armaturemeans includes an armature member having an outer end portion forengaging the jack and an inner end portion disposed adjacent to saidcoil means. said actuator assembly further including mounting means forsupporting said armature member for pivotal movement relative to saidcoil means, said mounting means including recess means for receiving aportion of said armature member, said recess means having an opening andbottom portion facing toward the outer end portion of said armaturemember, said armature member having a portion extending through saidopening into engagement with said bottom portion of said recess. saidopening having an area which is greater than the cross sectional area ofany portion of said armature member disposed within said recess in aplane parallel to said opening to enable said armature member to movefreely through said opening.

14. An actuator assembly as set forth in claim 13 wherein said firstspring means presses said actuator member against the bottom portion ofsaid recess means.

15. An actuator assembly as set forth in claim 14 wherein said inner endportion of said armature member is formed of a first metal and saidouter end portion of said armature member is formed of a second metalwhich is harder than said first metal, said outer end portion of saidarmature member including cam surface means formed of said second metalfor engaging the jack to move it between the knit and nonknit positions.

16. A knitting machine comprising a base, a plurality of knittingneedles, a plurality of longitudinally extending jacks each of which isoperatively connected with an associated one of said needles and has abutt which is movable between knit and non knit positions, said jacksbeing arranged in a plurality of groups of equal number with the ubttsof the jacks in each group being arranged in echelon formation which isthe same for each of the groups. carrier means connected with said baseand said jacks for sequentially moving the knitting needles andassociated jacks through a plurality of knitting stations, and aplurality of interchangeable actuator modules each of which is connectedwith said base at one of said knitting stations, each of said modulesincluding a first longitudinally extending support element. a secondlongitudinally extending support element spaced apart from said firstlongitudinally extending support element. and a longitudinally extendingcover member connected with and extending at least partially across thespace between said first and second support elements. said cover memberincluding means which at least partially defines a longitudinallyextending array of openings each of which has a stop surface extendingtransversely to said first and second support elements. each of saidmodules further including an array of electromagnetic actuators disposedin a single column between said first and second longitudinallyextending support elements with the number of electromagnetic actuatorsin the column being equal to the number of jacks in a group. each ofsaid electromagnetic actuators being associated with a different one ofthe openings in said cover member. each of said electromagneticactuators including coil means having a central axis extendingtransversely to the longitudinal axes of said first and second supportelements and of said jacks for providing a magnetic field uponenergization of said coil means, frame means extending between saidfirst and second support elements for supporting said coil means, saidframe means having a first side portion connected with said firstsupport element, a second side portion connected with said second support element and a central portion disposed intermediate said first andsecond side portions and connected with said coil means, an armaturemember pivotally connected with said frame means and extending throughone of said openings in said cover member, and means for supporting saidarmature member for pivotal movement between a first position in whichsaid armature member is disposed in abutting engagement with said stopsurface of the associated one of said openings and extends into the pathof movement of at least some of said jack butts and a second position inwhich said armature member is spaced apart from said stop surface.

17. A knitting machine as set forth in claim 16 wherein each of saidmodules further includes longitudinally extending register surface meansfor engaging the frame means of each of said electromagnetic actuatorsto position them along the central axes of said coil means with theouter end portions of said armature members in predetermined locationsrelative to said jacks, said register surface means being connected withsaid support elements and having a longitudinal axis extendingsubstantially parallel to the longitudinal axes of said jacks.

18. A knitting machine as set forth in claim 17 wherein said first andsecond support elements include second register surface means forengaging the frame means of each of said electromagnetic actuators toposition them along axes extending transversely to the central axes ofsaid coil means with the central axes of said coil means disposed in aflat plane defined by the central axes of a pair of said coil means.

19. A knitting machine as set forth in claim 16 further including firstregister surface means at each of the knitting stations for positioningsaid modules relative to said jacks along a first axis. and secondregister surface means at each of the knitting stations for positioningsaid modules relative to said jacks along a second axis extendingperpendicular to said first axis.

20. A knitting machine as set forth in claim 16 wherein said means forsupporting said armature member includes means for supporting saidarmature member for pivotal movement about an axis extendingtransversely to the central axis of said coil means and to thelongitudinal axes of said jacks.

21. An actuator assembly for effecting movement of a knitting machinejack between knit and nonknit positions. said actuator assemblycomprising an armature member pivotal between a first position in whichsaid armature member is ineffective to move the jack and a secondposition in which an outer end portion of said armature member iseffective to move the jack between the knit and nonknit positions, coilmeans for moving said armature member between the first and secondpositions, first mounting means connected with said coil means forengaging an inner end portion of said armature member at one location toat least partially support said armature member for pivotal movementbetween the first and second positions. second mounting means connectedwith said coil means and spaced apart from said first mounting means forengaging the inner end portion of said armature member at anotherlocation spaced from said one location to at least partially supportsaid armature member for pivotal movement between the first and secondpositions, said first and second mounting means each including recessmeans for receiving the inner end portion of said armature member, eachof said recess means having a bottom portion and an opening facingtoward the outer end portion of said armature and through which openingthe inner end portion of said armature member extends into abuttingengagement with the bottom portion of said recess means. and springmeans for pressing the inner end portion of said armature member againstsaid bottom portions of said recess means to retain said armature memberagainst outward movement away from said bottom portions of said recessmeans.

22. An actuator assembly as set forth in claim 21 wherein said springmeans is connected with said arma ture member and is effective to opposemovement of said armature member between the first and second positions.

23. An actuator assembly as set forth in claim 2] wherein said armaturemember has major and minor surfaces which intersect at said onelocation. said corner portion having an apex which is disposed inabutting engagement with said bottom portion of one of said recess meanswhen said armature member is in said first position.

24. An actuator assembly as set forth in claim 23 wherein said minorsurface of said actuator member is disposed in abutting engagement withsaid bottom por tion of said one recess means when said armature memberis in said second position.

25. An actuator assembly as set forth in claim 21 wherein a cam surfacemeans is formed on said outer end portion of said armature member topress against the jack and move it between the knit and nonknitpositions. said cam surface means having a longitudinal axis extendingat an angle relative to an axis about which said armature member pivotsbetween said first and second positions such that engagement of said camsurface means with the jack tends to rotate the actuator member about anaxis disposed intermediate said first and second mounting means.

26. An actuator assembly as set forth in claim 21 wherein said bottomportions of said recess means are at least partially defined by surfaceshaving areas which are equal to or less than the areas of the associatedone of said openings.

27. An actuator assembly as set forth in claim 26 wherein said bottomsurface of said recess means extend parallel to each other and an axisabout which said armature member pivots upon movement of said armaturemember between the first and second positions.

28. An actuator assembly as set forth in claim 2] further including aframe member having a plurality of interconnected leg sections includinga first leg section extending through said coil means. a second legsection disposed on one side of said first leg section. and a third legsection disposed on a side of said first leg section opposite said oneside. said first mounting means being connected with said second legsection. said second mounting means being connected with said third legsection.

29. An actuator assembly as set forth in claim 28 wherein said springmeans includes a beam spring member which extends between said secondand third leg sections.

30. A knitting machine comprising a base. a plurality of knittingneedles. a plurality of longitudinally extendingjacks each of which isconnected with an associated one of said needles and has a butt which ismovable between knit and nonknit positions. said jacks being arranged ina plurality of groups of equal number with the butts of the jacks ineach group being arranged in echelon formation which is the same foreach of the groups. carrier means connected with said base and saidjacks for sequentially moving the knitting needles and associated jacksthrough a pluraltiy of knitting stations. and a plurality ofinterchangeable actuator modules each of which is connected with saidbase at one of said knitting stations, each of said modules including anarray of electromagnetic actuators disposed in a single column with thenumber of electromagnetic actuators in the column being equal to thenumber of jacks in a group, each of said electromagnetic actuatorsincluding coil means having a central axis extending transversely to thelongitudinal axes of said jacks for providing a magnetic field uponenergization of said coil means. frame means for supporting said coilmeans. an armature member connected with said frame means. means forsupporting said armature member for pivotal movement about an axisextending transversely to the central axis of said coil means and to thelongitudinal axes of said jacks. and connector means for releasablyconneacting each of said modules with said base. the magnetic fieldemanating from said coil means of each of said electromagnetic actuatorsbeing effective upon energization thereof to attract said armaturemember toward said coil means with a magnetic force which increases atan increasing rate as said armature member moves toward said coil means.each of said electromagnetic actuators further including first springmeans for providing a first biasing force opposing movement of saidarmature member under the influence of the magnetic force emanating fromsaid coil means. can second spring means for providing a second biasingforce which is effective to oppose movement of said armature memberafter said armature member has moved against the influence of said firstbiasing force. said first and second spring means cooperating duringmovement of said armature member to provide a total biasing force whichincreases at a first rate during a initial portion of the movement ofsaid armature member and which increases at a second rate which isgreater than the first rate during a final portion of the movement ofsaid armature member.

3!. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station. a plurality ofjack means each of which is associated with one of said needles and isoperable between knit and nonknit conditions. and a plurality ofactuator means disposed at the knitting station for effecting operationof said 'jack means between the knit and nonknit conditions. each ofsaid ac tuator means including coil means energizable to provide amagnetic field. a frame member having a plurality of parallelinterconnected leg sections including a first leg section extendingthrough said coil means. a second leg section disposed on one side ofsaid first leg section. and a third leg section disposed on a side ofsaid first leg section opposite said one side, an armature membermovable under the influence of a magnetic field emanating from said coilmeans. said armature member being pivotal between a first position inwhich said armature member is ineffective to operate one of said jackmeans between the knit and nonknit conditions and a second position inwhich said armature member is effective to operate one of said jackmeans between the knit and nonknit conditions. said armature membeincluding a first porition adjacent to said second leg section and asecond portion disposed adjacent to said third leg section. first recessmeans connected with said second leg section for supporting said firstportion of said armature member for pivotal movement, said first recessmeans including a first bottom portion disposed inwardly of a firstoutwardly facing opening. said first portion of said armature memberextending through said first opening into abutting engagement with saidfirst bottom portion, said first portion of said armature member beingpivotal relative to said frame member at the location where said firstportion of said armature member engages said first bottom portion ofsaid first recess means, second recess means connected with said thirdleg section for supporting said second portion of said armature memberfor pivotal movement. said second recess means including a second bottomportion disposed inwardly of a second outwardly facing opening. saidsecond portion of said armature member extending through said secondopening into abutting engagement with said second bottom portion. saidsecond portion of said armature member being pivotal relative to saidframe member at the location where said second portion of said armaturemem ber engages said second bottom portion of said second recess means.

32. A knitting machine as set forth in claim 31 wherein each of saidactuator means further includes spring means for pressing said firstportion of said armature member against said first bottom portion ofsaid first recess means and for pressing said second portion of saidarmature member against said second bottom portion of said second recessmeans.

33. A knitting machine as set forth in claim 3] wherein said firstportion of said armature member includes side surface areas whichcooperate to define a first apex disposed in abutting engagement withsaid first bottom portion of said first recess means when said armaturemember is in one of said first and second positions. said second portionof said armature member including side surface areas which cooperate todefine a second apex disposed in abutting engagement with said secondbottom portion of said second recess means when said armature member isin one of said first and second position. said armature member beingpivotal about said first and second apexes during at least a portion ofthe movement of said armature member between said first and secondpositions.

34. A knitting machine as set forth in claim 33 wherein one of the sidesurface areas of said first portion of said armature member is disposedin abutting engagement with said first bottom portion of said firstrecess means when said armature member is in another one of said firstand second positions. one of said side surface areas of said secondportion of said armature member being disposed in abutting engagementwith said second bottom portion of said second recess means when saidarmature member is in said other one of said first and second positions.

35. A knitting machine as set forth in claim 33 wherein each.of saidactuator means further includes spring means for pressing said first andsecond apexes against said first and second bottom portions when saidarmature member is in said one of said first and second positions.

36. A knitting machine as set forth in claim 31 further including onespring member biasing said armature member toward one of said first andsecond positions and for pressing said first and second portions of saidarmature member against said bottom portions of said recess means.

37. An actuator assembly for effecting movement of a knitting machinejack between knit and nonknit positions. said actuator assemblycomprising a base member. an armature member connected with said basemember for pivotal movement relative to said base member between a firstposition in which said armature member is ineffective to move the jackand a second position in whcih an outer end portion of said armaturemember is effective to move the jack between the knit and nonknitpositions, coil means for providing a magnetic field to effect movementof said armature member between the first and second positions uponenergization of said coil means. mounting means connected with said basemember for engaging an inner end portion of said armature member to atleast partially support said armature member for pivotal movementbetween the first and second positions. said mounting means includingrecess means for receiving the inner end portion of said armaturemember, said recess means having a bottom portion and an opening throughwhich the inner end portion of said armature member extends intoabutting engagement with the bottom portion of said recess means, andspring means for pressing the inner end portion of said armature memberagainst said bottom portion of said recess means to retain said armaturemember against outward movement away form said bottom portion of saidrecess means and for biasing said armature member toward one of saidfirst and second positions.

38. An actuator assembly as set forth in claim 37 wherein said springmeans includes a beam spring connected with said base member and saidarmature member.

39. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station. a plurality ofjacts each of which is operatively connected with an associated one ofthe needles and has a butt which is movable between knit and nonknitposition. said jack butts being movable along a circular path throughthe knitting station by said needle carrier. and a plurality of actuatormeans at the knitting station for effecting movement of the jack buttsbetween the knit and nonknit positions. each of said actuator meansincluding a coil means for pro- 23 viding a magnetic field uponenergization of said coil means. a stationary frame member magnetizableby said coil means upon energization of said coil means. an armaturemember movable relative to said frame member between a first positionand a second position under the influence of a magnetic field emanatingfrom said coil means and frame member. said armature member including aninner portion disposed adjacent to said coil means formed of a firstmaterial having relatively low residual magnetism upon de-energizationof said coil means and an outer end portion disposed adjacent to saidjack butts and formed of a second material which is harder than saidfirst material. said outer end portion including can surface meansformed of said second material for engaging said jack butts. said camsurface means being movable by said armature member from a positionoffset from the path of movement of said jack butts through the knittingstation to a position disposed in the path of movement of said jackbutts through the knitting station upon movement of said armature memberfrom the first position to the second position. mounting means connectedwith said frame member for supporting said armature member for pivotalmovement between the first and second positions about a pivot axisextending transversely to a central axis of said coil means. and stopmeans for engaging said armature member at a location disposedintermediate said cam surface means and said pivot axis upon movement ofsaid armature member from the first position to the second position,said stop means includes a member formed of a nonmagnetizable materialto prevent engagement of said armature with said frame member uponmovement of said armature with said frame member upon movement of saidarmature from said first position to said second position upon energi'zation of said coil means.

40. A knitting machine as. set forth in claim 39 wherein said framemember has a plurality of parallel leg sections. a first one of said legsections extending through said coil means. a second one of saidlegsections being disposed on one side of said first leg section. and athird one of said leg sections being on a side of said first leg sectionopposite from said one side. said mounting means including firstmounting means connected with said second leg section and engaging afirst portion of said armature member and second mounting meansconnected with said third leg section and engaging a second portion ofsaid armature member.

UNITED STAIES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,896,639 Dat d July 29, 1975 I v Christiansen et al It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In claim 5, line 15 after "said" and before "side", insert --one--.

In claim 16, line 5 after "and" and before "positions", delete "nonknit" and insert -nonknit-.

In claim. 16, line 7 after "the" and before "of" delete "ubtts andinsert --butts--.

In claim 30, line 8, delete "lon formation" and insert -lonformation--.Q

In claim 30, line 38, delete "force" and insert field--, and

delete "can" and insert -and-.

V In claim 30, line 45 after "during", delete "a" and insert --an. Q

In claim 33, line 12, delete "position," and insert -positions,-.

In claim 37, line 8, delete "whcih" and insert --which--.

1' In claim 37, line 27, delete "form" and insert -from-.

In claim 39, line 3, delete "jacts" and insert -jacks--.

In claim 39, line 6, delete "position," and insert -positions,-,

In claim 39, line 25, delete "can" and insert -cam.

In claim 39, lines 44 and 45, after "armature" and before "from" delete"with said frame member upon movement of said armature".

Signed and Scaled this ninth Day Of Marc h1976 [SEAL] a Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oj'Parenrsand Trademarks

1. A knitting machine comprising needle carrier means for moving aplurality of knitting needles through a knitting station, a plurality ofjack means each of which is associated with one of said needles and isoperable between knit and nonknit conditions, and a plurality ofactuator means disposed at the knitting station for effecting operationof said jack means between the knit and nonknit conditions, each of saidactuator means including coil means energizable to provide a magneticfield, a frame member having a plurality of parallel interconnecteD legsections including a first leg section extending through said coilmeans, a second leg section disposed on one side of said first legsection, and a third leg section disposed on a side of said first legsection opposite said one side, an armature member movable under theinfluence of a magnetic field emanating from said coil means, andmounting means connected with said second and third leg sections forsupporting said armature member for pivotal movement between a firstposition in which said armature member is ineffective to operate one ofsaid jack means between the knit and nonknit conditions and a secondposition in which said armature member is effective to operate one ofsaid jack means between the knit and nonknit conditions, the magneticfield emanating from said coil means of each of said actuator meansbeing effective upon energization thereof to attract said armaturemember with a magnetic force which increases at an increasing rate assaid armature member moves between the first and second positions, eachof said actuator means further including first spring means forproviding a first biasing force opposing movement of said armaturemember between the first and second positions under the influence of themagnetic field emanating from said coil means, and second spring meansfor providing a second biasing force which is effective to opposemovement of said armature member after said armature member has movedpart way between said first and second positions against the influenceof said first biasing force, said first and second spring meanscooperating during movement of said armature member to provide a totalbiasing force which increases at a first rate during an initial portionof the movement of said armature member between the first and secondpositions and which increases at a second rate which is greater than thefirst rate during a final portion of the movement of said armaturemember between the first and second positions.
 2. A knitting machine asset forth in cliam 1 further including support means for supporting saidactuator means in a linear array at the knitting station, said supportmeans including a first longitudinally extending support elementconnected with the second leg section of said frame members and a secondlongitudinally extending support element connected with the third legsection of said frame members.
 3. A knitting machine comprising needlecarrier means for moving a plurality of knitting needles through aknitting station, a plurality of jack means each of which is associatedwith one of said needles and is operable between knit and nonknitconditions, and a plurality of actuator means disposed at the knittingstation for effecting operation of said jack means between the knit andnonknit conditions, each of said actuator means including coil meansenergizable to provide a magnetic field, a frame member having aplurality of parallel interconnected leg sections including a first legsection extending through said coil means, a second leg section disposedon one side of said first leg section, and a third leg section disposedon a side of said first leg section opposite said one side, an armaturemember movable under the influence of a magnetic field emanating fromsaid coil means, mounting means connected with said second and third legsections for supporting said armature member for pivotal movementbetween a first position in which said armature member is ineffective tooperate one of said jack means between the knit and nonknit conditionsand a second position in which said armature member is effective tooperate one of said jack means between the knit and nonknit conditions,and spring means for providing a biasing force opposing movement of saidarmature member between the first and second positions, said springmeans including a beam spring member extending transversely to said legsections and having a central porition connected to said armaturemember, one end portion connected with said second leg sectIon, andanother end portion connected with said third leg section.
 4. A knittingmachine as set forth in claim 3 wherein said mounting means for each ofsaid actuator means includes a first recess means connected with saidsecond leg section for engaging an inner end portion of said armaturemember at one location and a second recess means connected with saidthird leg section for engaging the inner end portion of said armaturemember at another location spaced from the one location, each of saidrecess means including a bottom portion disposed inwardly of anoutwardly facing opening and through which opening the inner end portionof said armature member extends.
 5. A knitting machine comprising needlecarrier means for moving a plurality of knitting needles through aknitting station, a plurality of jack means each of which is associatedwith one of said needles and is operable between knit and nonknitconditions, and a plurality of actuator means disposed at the knittingstation for effecting operation of said jack means between the knit andnonknit conditions, each of said actuator means including coil meansenergizable to provide a magnetic field, a frame member having aplurality of parallel interconnected leg sections including a first legsection extending through said coil means, a second leg section disposedon one side of said first leg section, and a third leg section disposedon a side of said first leg section opposite said side, an armaturemember movable under the influence of a magnetic field emanating fromsaid coil means, and mounting means connected with said second and thirdleg sections for supporting said armature member for pivotal movementbetween a first position in which said armature member is ineffective tooperate one of said jack means between the knit and nonknit conditionsand a second position in which said armature member is effective tooperate one of said jack means between the knit and nonknit conditions,said mounting means for each of said actuator means including a firstrecess means connected with said second leg section for engaging aninner end portion of said armature member at one location and a secondrecess means connected with said third leg section for engaging theinner end portion of said armature member at another location spacedfrom the one location, each of said recess means including a bottomportion disposed inwardly of an outwardly facing opening and throughwhich opening the inner end portion of said armature member extends,each of said actuator means further including spring means for opposingmovement of said armature member between the first and second positionsand for pressing the inner end portion of said armature member againstthe bottom portions of said first and second recess means.
 6. A knittingmachine as set forth in claim 5 wherein said spring means includes alongitudinally extending spring member connected with said second andthird leg sections at its outer end portions, said spring member havinga portion disposed betweeen the outer end portions connected with saidarmature member.
 7. A knitting machine as set forth in claim 5 whereinapexes formed by the intersection of side surfaces of said armaturemember are disposed in abutting engagement with the bottom portions ofsaid first and second recess means when said armature member is in oneof said first and second positions.
 8. A knitting machine as set forthin claim 7 wherein one of the side surfaces of said armature member isdisposed in abutting engagement with the bottom portion of at least oneof said recess means when said armature member is in another one of saidfirst and second positions.
 9. A knitting machine as set forth in claim5 wherein said armature member of each of said actuator means includesan inner end portion disposed in engagement with said mounting means andformed of a first metal and an outer end portion disposed adjacent tosaid jack means and formed of a second metal which is harder thaN saidfirst metal, said outer end portion of said armature member includingcam surface means formed of said second metal for engaging said jackmeans.
 10. An actuator assembly for effecting movement of a knittingmachine jack between knit and nonknit positions, said actuator assemblycomprising armature means movable between a first position in which saidarmature means is ineffective to move the jack and a second position inwhich said armature means is effective to move the jack between the knitand nonknit positions, coil means for moving said armature means betweenthe first and second positions upon energization of said coil means,said coil means being energizable to attract said armature means with amagnetic force which increases at an increasing rate as said armaturemeans moves between the first and second positions, first spring meansfor providing a first biasing force opposing movement of said armaturemeans between the first and second positions under the influence of themagnetic force, and second spring means for providing a second biasingforce opposing movement of said armature means between the first andsecond positions after movement of said armature means against the firstbiasing force, said first and second spring means cooperating duringmovement of said armature means to provide a total biasing force whichincreases at a first rate during an initial portion of the movement ofsaid armature means between the first and second positions and whichincreases at a second rate which is greater than the first rate during afinal portion of the movement of said armature means between the firstand second positions.
 11. An actuator assembly as set forth in claim 10further including a frame member having a plurality of interconnectedleg sections including a first leg section extending through said coil,means, a second leg section disposed on one side of said first legsection, and a third leg section disposed on a side of said first legsection opposite said one side, and mounting means connected with saidsecond and third leg sections for supporting said armature means forpivotal movement between the first and second positions.
 12. An actuatorassembly as set forth in claim 11 wherein said first spring meansincludes a longitudinally extending spring member connected to saidsecond and third leg sections and said armature means intermediate theconnections to said second and third leg means.
 13. An actuator assemblyas set forth in claim 10 wherein said armature means includes anarmature member having an outer end portion for engaging the jack and aninner end portion disposed adjacent to said coil means, said actuatorassembly further including mounting means for supporting said armaturemember for pivotal movement relative to said coil means, said mountingmeans including recess means for receiving a portion of said armaturemember, said recess means having an opening and bottom portion facingtoward the outer end portion of said armature member, said armaturemember having a portion extending through said opening into engagementwith said bottom portion of said recess, said opening having an areawhich is greater than the cross sectional area of any portion of saidarmature member disposed within said recess in a plane parallel to saidopening to enable said armature member to move freely through saidopening.
 14. An actuator assembly as set forth in claim 13 wherein saidfirst spring means presses said actuator member against the bottomportion of said recess means.
 15. An actuator assembly as set forth inclaim 14 wherein said inner end portion of said armature member isformed of a first metal and said outer end portion of said armaturemember is formed of a second metal which is harder than said firstmetal, said outer end portion of said armature member including camsurface means formed of said second metal for engaging the jack to moveit between the knit and nonknit positions.
 16. A knitting machinecomprising a bAse, a plurality of knitting needles, a plurality oflongitudinally extending jacks each of which is operatively connectedwith an associated one of said needles and has a butt which is movablebetween knit and non knit positions, said jacks being arranged in aplurality of groups of equal number with the ubtts of the jacks in eachgroup being arranged in echelon formation which is the same for each ofthe groups, carrier means connected with said base and said jacks forsequentially moving the knitting needles and associated jacks through aplurality of knitting stations, and a plurality of interchangeableactuator modules each of which is connected with said base at one ofsaid knitting stations, each of said modules including a firstlongitudinally extending support element, a second longitudinallyextending support element spaced apart from said first longitudinallyextending support element, and a longitudinally extending cover memberconnected with and extending at least partially across the space betweensaid first and second support elements, said cover member includingmeans which at least partially defines a longitudinally extending arrayof openings each of which has a stop surface extending transversely tosaid first and second support elements, each of said modules furtherincluding an array of electromagnetic actuators disposed in a singlecolumn between said first and second longitudinally extending supportelements with the number of electromagnetic actuators in the columnbeing equal to the number of jacks in a group, each of saidelectromagnetic actuators being associated with a different one of theopenings in said cover member, each of said electromagnetic actuatorsincluding coil means having a central axis extending transversely to thelongitudinal axes of said first and second support elements and of saidjacks for providing a magnetic field upon energization of said coilmeans, frame means extending between said first and second supportelements for supporting said coil means, said frame means having a firstside portion connected with said first support element, a second sideportion connected with said second support element and a central portiondisposed intermediate said first and second side portions and connectedwith said coil means, an armature member pivotally connected with saidframe means and extending through one of said openings in said covermember, and means for supporting said armature member for pivotalmovement between a first position in which said armature member isdisposed in abutting engagement with said stop surface of the associatedone of said openings and extends into the path of movement of at leastsome of said jack butts and a second position in which said armaturemember is spaced apart from said stop surface.
 17. A knitting machine asset forth in claim 16 wherein each of said modules further includeslongitudinally extending register surface means for engaging the framemeans of each of said electromagnetic actuators to position them alongthe central axes of said coil means with the outer end portions of saidarmature members in predetermined locations relative to said jacks, saidregister surface means being connected with said support elements andhaving a longitudinal axis extending substantially parallel to thelongitudinal axes of said jacks.
 18. A knitting machine as set forth inclaim 17 wherein said first and second support elements include secondregister surface means for engaging the frame means of each of saidelectromagnetic actuators to position them along axes extendingtransversely to the central axes of said coil means with the centralaxes of said coil means disposed in a flat plane defined by the centralaxes of a pair of said coil means.
 19. A knitting machine as set forthin claim 16 further including first register surface means at each ofthe knitting stations for positioning said modules relative to saidjacks along a first axis, and second register surface means at each ofthe knittiNg stations for positioning said modules relative to saidjacks along a second axis extending perpendicular to said first axis.20. A knitting machine as set forth in claim 16 wherein said means forsupporting said armature member includes means for supporting saidarmature member for pivotal movement about an axis extendingtransversely to the central axis of said coil means and to thelongitudinal axes of said jacks.
 21. An actuator assembly for effectingmovement of a knitting machine jack between knit and nonknit positions,said actuator assembly comprising an armature member pivotal between afirst position in which said armature member is ineffective to move thejack and a second position in which an outer end portion of saidarmature member is effective to move the jack between the knit andnonknit positions, coil means for moving said armature member betweenthe first and second positions, first mounting means connected with saidcoil means for engaging an inner end portion of said armature member atone location to at least partially support said armature member forpivotal movement between the first and second positions, second mountingmeans connected with said coil means and spaced apart from said firstmounting means for engaging the inner end portion of said armaturemember at another location spaced from said one location to at leastpartially support said armature member for pivotal movement between thefirst and second positions, said first and second mounting means eachincluding recess means for receiving the inner end portion of saidarmature member, each of said recess means having a bottom portion andan opening facing toward the outer end portion of said armature andthrough which opening the inner end portion of said armature memberextends into abutting engagement with the bottom portion of said recessmeans, and spring means for pressing the inner end portion of saidarmature member against said bottom portions of said recess means toretain said armature member against outward movement away from saidbottom portions of said recess means.
 22. An actuator assembly as setforth in claim 21 wherein said spring means is connected with saidarmature member and is effective to oppose movement of said armaturemember between the first and second positions.
 23. An actuator assemblyas set forth in claim 21 wherein said armature member has major andminor surfaces which intersect at said one location, said corner portionhaving an apex which is disposed in abutting engagement with said bottomportion of one of said recess means when said armature member is in saidfirst position.
 24. An actuator assembly as set forth in claim 23wherein said minor surface of said actuator member is disposed inabutting engagement with said bottom portion of said one recess meanswhen said armature member is in said second position.
 25. An actuatorassembly as set forth in claim 21 wherein a cam surface means is formedon said outer end portion of said armature member to press against thejack and move it between the knit and nonknit positions, said camsurface means having a longitudinal axis extending at an angle relativeto an axis about which said armature member pivots between said firstand second positions such that engagement of said cam surface means withthe jack tends to rotate the actuator member about an axis disposedintermediate said first and second mounting means.
 26. An actuatorassembly as set forth in claim 21 wherein said bottom portions of saidrecess means are at least partially defined by surfaces having areaswhich are equal to or less than the areas of the associated one of saidopenings.
 27. An actuator assembly as set forth in claim 26 wherein saidbottom surface of said recess means extend parallel to each other and anaxis about which said armature member pivots upon movement of saidarmature member between the first and second positions.
 28. An actuatorassembly as set forth in claim 21 further including a frame memberhaving a plurality of interconnected leg sections including a first legsection extending through said coil means, a second leg section disposedon one side of said first leg section, and a third leg section disposedon a side of said first leg section opposite said one side, said firstmounting means being connected with said second leg section, said secondmounting means being connected with said third leg section.
 29. Anactuator assembly as set forth in claim 28 wherein said spring meansincludes a beam spring member which extends between said second andthird leg sections.
 30. A knitting machine comprising a base, aplurality of knitting needles, a plurality of longitudinally extendingjacks each of which is connected with an associated one of said needlesand has a butt which is movable between knit and nonknit positions, saidjacks being arranged in a plurality of groups of equal number with thebutts of the jacks in each group being arranged in echelon formationwhich is the same for each of the groups, carrier means connected withsaid base and said jacks for sequentially moving the knitting needlesand associated jacks through a pluraltiy of knitting stations, and aplurality of interchangeable actuator modules each of which is connectedwith said base at one of said knitting stations, each of said modulesincluding an array of electromagnetic actuators disposed in a singlecolumn with the number of electromagnetic actuators in the column beingequal to the number of jacks in a group, each of said electromagneticactuators including coil means having a central axis extendingtransversely to the longitudinal axes of said jacks for providing amagnetic field upon energization of said coil means, frame means forsupporting said coil means, an armature member connected with said framemeans, means for supporting said armature member for pivotal movementabout an axis extending transversely to the central axis of said coilmeans and to the longitudinal axes of said jacks, and connector meansfor releasably conneacting each of said modules with said base, themagnetic field emanating from said coil means of each of saidelectromagnetic actuators being effective upon energization thereof toattract said armature member toward said coil means with a magneticforce which increases at an increasing rate as said armature membermoves toward said coil means, each of said electromagnetic actuatorsfurther including first spring means for providing a first biasing forceopposing movement of said armature member under the influence of themagnetic force emanating from said coil means, can second spring meansfor providing a second biasing force which is effective to opposemovement of said armature member after said armature member has movedagainst the influence of said first biasing force, said first and secondspring means cooperating during movement of said armature member toprovide a total biasing force which increases at a first rate during ainitial portion of the movement of said armature member and whichincreases at a second rate which is greater than the first rate during afinal portion of the movement of said armature member.
 31. A knittingmachine comprising needle carrier means for moving a plurality ofknitting needles through a knitting station, a plurality of jack meanseach of which is associated with one of said needles and is operablebetween knit and nonknit conditions, and a plurality of actuator meansdisposed at the knitting station for effecting operation of said jackmeans between the knit and nonknit conditions, each of said actuatormeans including coil means energizable to provide a magnetic field, aframe member having a plurality of parallel interconnected leg sectionsincluding a first leg section extending through said coil means, asecond leg section disposed on one side of said first leg section, and athird leg section disposed on a side of said first leg section oppositesaid one side, an armature member movable undeR the influence of amagnetic field emanating from said coil means, said armature memberbeing pivotal between a first position in which said armature member isineffective to operate one of said jack means between the knit andnonknit conditions and a second position in which said armature memberis effective to operate one of said jack means between the knit andnonknit conditions, said armature membe including a first poritionadjacent to said second leg section and a second portion disposedadjacent to said third leg section, first recess means connected withsaid second leg section for supporting said first portion of saidarmature member for pivotal movement, said first recess means includinga first bottom portion disposed inwardly of a first outwardly facingopening, said first portion of said armature member extending throughsaid first opening into abutting engagement with said first bottomportion, said first portion of said armature member being pivotalrelative to said frame member at the location where said first portionof said armature member engages said first bottom portion of said firstrecess means, second recess means connected with said third leg sectionfor supporting said second portion of said armature member for pivotalmovement, said second recess means including a second bottom portiondisposed inwardly of a second outwardly facing opening, said secondportion of said armature member extending through said second openinginto abutting engagement with said second bottom portion, said secondportion of said armature member being pivotal relative to said framemember at the location where said second portion of said armature memberengages said second bottom portion of said second recess means.
 32. Aknitting machine as set forth in claim 31 wherein each of said actuatormeans further includes spring means for pressing said first portion ofsaid armature member against said first bottom portion of said firstrecess means and for pressing said second portion of said armaturemember against said second bottom portion of said second recess means.33. A knitting machine as set forth in claim 31 wherein said firstportion of said armature member includes side surface areas whichcooperate to define a first apex disposed in abutting engagement withsaid first bottom portion of said first recess means when said armaturemember is in one of said first and second positions, said second portionof said armature member including side surface areas which cooperate todefine a second apex disposed in abutting engagement with said secondbottom portion of said second recess means when said armature member isin one of said first and second position, said armature member beingpivotal about said first and second apexes during at least a portion ofthe movement of said armature member between said first and secondpositions.
 34. A knitting machine as set forth in claim 33 wherein oneof the side surface areas of said first portion of said armature memberis disposed in abutting engagement with said first bottom portion ofsaid first recess means when said armature member is in another one ofsaid first and second positions, one of said side surface areas of saidsecond portion of said armature member being disposed in abuttingengagement with said second bottom portion of said second recess meanswhen said armature member is in said other one of said first and secondpositions.
 35. A knitting machine as set forth in claim 33 wherein eachof said actuator means further includes spring means for pressing saidfirst and second apexes against said first and second bottom portionswhen said armature member is in said one of said first and secondpositions.
 36. A knitting machine as set forth in claim 31 furtherincluding one spring member biasing said armature member toward one ofsaid first and second positions and for pressing said first and secondportions of said armature member against said bottom portions of saidrecess means.
 37. An actuatOr assembly for effecting movement of aknitting machine jack between knit and nonknit positions, said actuatorassembly comprising a base member, an armature member connected withsaid base member for pivotal movement relative to said base memberbetween a first position in which said armature member is ineffective tomove the jack and a second position in whcih an outer end portion ofsaid armature member is effective to move the jack between the knit andnonknit positions, coil means for providing a magnetic field to effectmovement of said armature member between the first and second positionsupon energization of said coil means, mounting means connected with saidbase member for engaging an inner end portion of said armature member toat least partially support said armature member for pivotal movementbetween the first and second positions, said mounting means includingrecess means for receiving the inner end portion of said armaturemember, said recess means having a bottom portion and an opening throughwhich the inner end portion of said armature member extends intoabutting engagement with the bottom portion of said recess means, andspring means for pressing the inner end portion of said armature memberagainst said bottom portion of said recess means to retain said armaturemember against outward movement away form said bottom portion of saidrecess means and for biasing said armature member toward one of saidfirst and second positions.
 38. An actuator assembly as set forth inclaim 37 wherein said spring means includes a beam spring connected withsaid base member and said armature member.
 39. A knitting machinecomprising needle carrier means for moving a plurality of knittingneedles through a knitting station, a plurality of jacts each of whichis operatively connected with an associated one of the needles and has abutt which is movable between knit and nonknit position, said jack buttsbeing movable along a circular path through the knitting station by saidneedle carrier, and a plurality of actuator means at the knittingstation for effecting movement of the jack butts between the knit andnonknit positions, each of said actuator means including a coil meansfor providing a magnetic field upon energization of said coil means, astationary frame member magnetizable by said coil means uponenergization of said coil means, an armature member movable relative tosaid frame member between a first position and a second position underthe influence of a magnetic field emanating from said coil means andframe member, said armature member including an inner portion disposedadjacent to said coil means formed of a first material having relativelylow residual magnetism upon de-energization of said coil means and anouter end portion disposed adjacent to said jack butts and formed of asecond material which is harder than said first material, said outer endportion including can surface means formed of said second material forengaging said jack butts, said cam surface means being movable by saidarmature member from a position offset from the path of movement of saidjack butts through the knitting station to a position disposed in thepath of movement of said jack butts through the knitting station uponmovement of said armature member from the first position to the secondposition, mounting means connected with said frame member for supportingsaid armature member for pivotal movement between the first and secondpositions about a pivot axis extending transversely to a central axis ofsaid coil means, and stop means for engaging said armature member at alocation disposed intermediate said cam surface means and said pivotaxis upon movement of said armature member from the first position tothe second position, said stop means includes a member formed of anonmagnetizable material to prevent engagement of said armature withsaid frame member upon movement of said armature with said frame memberupon movement of said armature from said first positioN to said secondposition upon energization of said coil means.
 40. A knitting machine asset forth in claim 39 wherein said frame member has a plurality ofparallel leg sections, a first one of said leg sections extendingthrough said coil means, a second one of said leg sections beingdisposed on one side of said first leg section, and a third one of saidleg sections being on a side of said first leg section opposite fromsaid one side, said mounting means including first mounting meansconnected with said second leg section and engaging a first portion ofsaid armature member and second mounting means connected with said thirdleg section and engaging a second portion of said armature member.